Recently, a three-dimensionally stacked nonvolatile semiconductor storage device has been proposed in which multilayer conductive films are collectively processed to increase the memory storage capacity. This nonvolatile semiconductor storage device includes a structural body with insulating films and electrode films alternately stacked therein, silicon pillars penetrating through the structural body, and a memory film between the silicon pillar and the electrode film. In this structure, a memory cell is formed at the intersection between the silicon pillar and each electrode film.
The three-dimensionally stacked nonvolatile semiconductor storage device is manufactured as follows. First, memory holes penetrating through the stacked body of conductive films are formed. A charge accumulation film is formed on the sidewall of the memory hole. Then, silicon constituting a channel is formed in the memory hole.
In such a nonvolatile semiconductor storage device, improvement in the controllability of memory cells is desired.